JPH0129805B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a polymerizable resin composition comprising a melamine group-containing thermosetting resin that has thermosetting properties due to polymerization of ethylenically unsaturated bonds and a polymerization initiator. Melamine resin has high hardness, high flame retardancy and heat resistance, and also has excellent electrical properties such as arc resistance and tracking resistance, so it has a wide range of uses such as decorative boards, electrical parts, tableware, etc. . Melamine resins, like phenolic resins and urea resins, are produced by a condensation reaction between melamine and formaldehyde. However, this production method has disadvantages in terms of environment and energy consumption, such as the smell of formalin gas during the reaction and the need for high temperature and pressure for the reaction. Attempts are known to provide thermoset properties and to provide heat curing by addition polymerization of ethylenically unsaturated bonds instead of relying on methylolation and methylenation with formaldehyde. For example, an alkyl ether derivative of methylolmelamine is transetherified with a hydroxyalkyl (meth)acrylate to introduce an ethylenically unsaturated bond (U.S. Patent No.
3020255 specification). Although it is not necessarily clear what kind of compound is obtained in this case, it is presumed that hydroxyalkyl (meth)acrylate is bonded to the methylol group of methylolmelamine through an ether bond because of transetherification. be done. There is also a product in which ethylenically unsaturated bonds are introduced by the reaction of methylolmelamine (or its alkyl ether derivative) and hydroxyalkyl (meth)acrylate (British Patent No. 628150).
(see specification). Although it is not necessarily clear what kind of compound is obtained in this case, it appears that hydroxyalkyl (meth)acrylate is bonded to the methylol group of methylolmelamine via an ether bond. However, according to the knowledge of the present inventors, cured products obtained by thermally polymerizing these materials tend to easily swell in hot water and turn white. In addition, heat resistance and rigidity are low. In order to provide a solution to the above point, the present inventors have developed an alkyl etherified melamine compound using acrylic acid, an α-alkyl-substituted acrylic acid compound, or an acrylamide-based melamine compound in order to provide thermosetting properties through ethylenically unsaturated bonds. He previously filed an application for a method for producing a thermosetting resin by reacting with a compound (see Japanese Patent Application No. 1983-93060 and the specification filed on August 19, 1980). These thermosetting resins themselves can be heated to
Alternatively, it is polymerized in the presence of a polymerization initiator to form a tough cured product. The thermosetting resin obtained by reacting this alkyl etherified melamine compound with acrylic acid or an α-lower alkyl-substituted acrylic acid compound has a low viscosity, is easy to handle, and has a low heat distortion temperature of the resulting cured product. Although it has many advantages, it has been found that depending on the type of alkyl etherified melamine compound used as the raw material, when the cured product is used for a long period of time in boiling water at 100°C, the transparent cured product turns into an opaque cured product. In addition, the thermosetting resin obtained by reacting an alkyl etherified melamine compound with acrylamide shows no change in appearance even if the transparent cured product is exposed to boiling water for a long period of time, but the heat distortion temperature of the cured product is is approximately 40 to 50°C lower than the above-mentioned cured product, and the viscosity of the thermosetting resin itself at 25°C is approximately
30,000 centipoise (CPS) or more, and to use it as a casting or impregnating material
It is necessary to dilute with a large amount of ethylenically unsaturated monomer such as methyl methacrylate. and,
Use of a large amount of diluent such as styrene is not preferable because it reduces the impact resistance, heat resistance, etc. of the resulting cured product. The present invention was made for the purpose of improving the drawbacks of the thermosetting resin of the previous application, and is a thermosetting resin that has a low viscosity, is easy to handle, and provides a cured product with excellent heat resistance and hot water resistance. A composition is provided. The object of the present invention is achieved by a thermosetting resin composition comprising the following components A) and B). A Component The ratio of acrylic acid and/or α-lower alkyl substituted acrylic acid to acrylamide and/or α-lower alkyl substituted acrylamide is 0.15/0.85
~0.85/0.15 molar ratio mixture and the following general formula []
Reaction product with an alkyl etherified melamine compound represented by [In the formula, R' each represents a hydrocarbon group having 1 to 4 carbon atoms, R is a methyl group, a phenyl group, -N
(CH ₂ OR') ₂ (R' is a hydrocarbon group having 1 to 4 carbon atoms, which is the same as or different from R' above), or an organic group represented by the following formula. (Y is -CH ₂ OR' or hydrogen, R' is a hydrocarbon group having 1 to 4 carbon atoms, which is the same as or different from R' above)] B Component Polymerization initiator. The reaction product of component A) is a melamine group-containing acrylate represented by the following general formula []. [In the formula, R is a methyl group, a phenyl group,

[Formula] or an organic group represented by the following formula. Y each represents hydrogen or Z ¹¹ . ^Z1 to ^Z11 each represent _-CH2OCOCR1 ⁼ _CH2 , _-CH2NHCOCR1 ⁼ _CH2 or _-CH2OR2 ^. At least one of Z ¹ to Z ¹¹ is -
CH ₂ OCOCR ¹ = CH ₂ or -CH ₂ NHCOCR ¹ =
CH ₂ and the acrylic compound represented by the general formula [] -CH ₂ OCOCR ¹ = CH ₂ and -
The average molar ratio of CH ₂ NHCOCR ¹ = CH ₂ is 0.15/
It is 0.85-0.85/0.15. R ¹ is -H or -CH ₃
, and R ² represents an alkyl group having 1 to 4 carbon atoms. ] The reaction product of component A) [ ] is an alkyl etherified melamine compound represented by the following formula [ ] and acrylic acid or an α-alkyl substituted acrylic acid compound (hereinafter, both are collectively referred to as "acrylic acid compound") ) and acrylamide or α-alkyl-substituted acrylamide (hereinafter both are collectively referred to as "acrylamide-based compounds")
It is obtained by reacting with a mixture of 0.15/0.85 to 0.85/0.15 molar ratio. The reaction between the alkyl etherified melamine and the mixture of an acrylic acid compound and an acrylamide compound is carried out at 50 to 150°C, preferably at 100 to 130°C.
is carried out in the presence of a catalyst. The reaction time varies depending on the distillation rate of the alkanol (R'OH) generated as the reaction progresses, but is about 2 to 20 hours when the alkanol is methanol. This reaction can and usually is carried out without the use of a solvent, but it can also be carried out in the presence of a suitable solvent or dispersion medium if desired. Examples of the solvent or dispersion medium in this case include those inert with respect to the reaction, such as hydrocarbons and halohydrocarbons. The molar ratio of the mixture of the acrylic acid compound and the acrylamide compound to the alkyl etherified melamine compound () is about 1/1 to 6/1, preferably about 2/1 to 4/1. It's normal. The specific molar ratio is determined by the number of moles of the acrylic acid compound and the acrylamide compound bound to the compound (). Further, the blending ratio of the acrylic acid compound and the acrylamide compound is 0.15:0.85 to 0.85:0.15 (molar ratio), preferably 0.50:0.50 to 0.85:0.15. If the amount of acrylic acid compound in the mixture is less than 15 mol%, the viscosity of the obtained component A) at 25°C is a viscosity suitable for casting materials and impregnation materials.
It is difficult to keep it below 10000CPS. Also,
The heat deformation temperature of the cured product tends to be less than 120°C, making it impractical as an electrical insulation material or sealing material that requires heat resistance. On the other hand, if the content exceeds 85 mol%, the resulting cured product will not have sufficient improvement in hot water resistance, and when the cured product is exposed to boiling water for a long period of time, the appearance may change from transparent to opaque. In addition, the higher the blending amount of the acrylic acid compound, the lower the viscosity of the thermosetting resin obtained, and
The solubility in styrene is improved, and the heat resistance of the cured product is also improved.
Preferably, it is used in a proportion of 85 mol%. Next, let's talk about raw materials. The alkyl etherified melamine compound represented by the general formula () has already been industrially produced in large quantities and is widely used mainly in the paint field as a crosslinking agent for various alkyds, acrylic polymers, etc. It is easily available. Some specific examples of this alkyl etherified melamine compound are as follows. Hexamethoxymethylmelamine, pentamethoxymethylmelamine, tetramethoxymethylmelamine, trimethoxymethylmelamine, tributoxymethylmelamine, hexaethoxymethylmelamine, pentaethoxymethylmelamine, tetraethoxymethylmelamine, trimethoxymethyl-diethoxymelamine, triethoxy Methyl-dibutoxymethylmelamine, hexapropoxymethylmelamine, tripropoxymethylmelamine, dibutoxymethylmelamine, trimethoxymethylmelamine, dipropoxymelamine, hexabutoxymethylmelamine, monomethoxymethylmelamine, tetrabutoxymethylmelamine, tetramethoxymethylmelamine , methylguanamine, dimethoxymethylguanamine, dibutoxymethylguanamine, methylguanamine, monomethoxymethylguanamine, tripropoxymethylguanamine, methylguanamine, tetramethoxymethylguanamine, tetramethoxymethylguanamine, benzoguanamine, tetrabutoxymethylguanamine, benzoguanamine, tetrabutoxy Methylguanamine, methylguanamine, dimethoxymethylguanamine,
Dibutoxymethyl-benzoguanamine and mixtures thereof. Particularly suitable for the purposes of the present invention are those of the formula () in which R' is a methyl group and R is -N(CH ₂ OCH ₃ ) ₂ or a phenyl group. Next, as the acrylic acid or α-lower alkyl substituted acrylic acid, acrylic acid, methacrylic acid, α-propylacrylic acid, α-butylacrylic acid, and mixtures thereof are generally suitable. Furthermore, acrylamide and α-lower alkyl-substituted acrylamide include acrylamide, methacrylamide, α-propylacrylamide,
α-Butylacrylamide, and mixtures thereof are generally suitable. As the α-lower alkyl group, those having 1 to 4 carbon atoms are generally suitable. As the catalyst, those effective in forming an ester from a carboxylic acid and an alkanol are generally suitable, but those made of organic acids such as para-toluenesulfonic acid are particularly preferred. For example, in the case of para-toluenesulfonic acid, the amount of catalyst used is about 100 ppm to 1% by weight, preferably 1000 ppm to 1% by weight, based on the total amount of compound (), acrylic acid compound, and acrylamide compound.
It is usually around 5000ppm. Since acrylic acid and acrylamide compounds are present as reactants and in the products in the reaction system according to the invention, it is generally necessary to prevent their polymerization. Various compounds are known for preventing the polymerization of ethylenically unsaturated bonds, and any appropriate compound can be used in the present invention. Specifically, for example, phenolic compounds,
There are amine compounds and air. When air is blown into the reaction system, it can not only prevent polymerization but also promote the distillation of alkanol produced.
Blowing air into the reaction system is preferred.
Note that since air alone may not have sufficient polymerization inhibitory effect, it is preferable to use a polymerization inhibitor other than air in combination. This reaction can be carried out according to various operating modes. Specifically, for example, an alkyl etherified melamine compound () is added to a reactor equipped with a stirring device, a cooler, and an air blowing device.
Then, the acrylic acid compound, acrylamide compound, and catalyst (in some cases, a solvent or dispersion medium) are charged, and a small amount (150 to 600 c.c./min) of air is blown into the reaction system (liquid phase). Raise the temperature to Distillation of alkanol begins when the reaction system temperature reaches around 100°C, and the reaction is terminated by raising the temperature to around 125 to 150°C and continuing heating until the distillation of alkanol stops. The product obtained by this reaction is obtained by esterifying and amidating the methylol group of a methylolmelamine compound with acrylic acid (or its α-lower alkyl substituted product) and acrylamide (or its α-lower alkyl substituted product). It is understood that it corresponds to a chemical compound. In addition, when R′ of the compound represented by the general formula () is hydrogen, in the presence of an esterification catalyst such as p-toluenesulfonic acid, the self-condensation reaction of the compound represented by the general formula () takes priority, and the The reaction between the compound and the acrylic compound is rate-limiting. The thermosetting resin of component A obtained by the above reaction is generally a pale yellow transparent viscous liquid. Since this thermosetting resin has ethylenically unsaturated bonds derived from acrylic acid compounds and acrylamide compounds, it is polymerized and cured by radical polymerization (or ionic polymerization in some cases). The means for curing the thermosetting resin of component A) may be any suitable method that can be used for radical polymerization of ethylenically unsaturated bonds. Specifically, for example, heating, irradiation with high-energy radiation, irradiation with ultraviolet rays or visible light, decomposition of a blended radical polymerization or ionic polymerization initiator, and others are possible.
One of the preferred curing means consists of blending a radical polymerization initiator, such as an organic peroxide, with a redox catalyst, if necessary, and heating, if necessary. Furthermore, the thermosetting resin of component A) can be cured into an appropriate shape in the form of a solution dissolved in an ethylenically unsaturated monomer and, if necessary, together with an appropriate filler or reinforcing agent. The polymerization initiator of component B) differs depending on the curing mode to be employed. For example, in the case of ultraviolet curing, examples include benzophenone, benzoin ethers, anthraquinones, etc., and in the case of heat curing, examples include azo compounds, organic peroxides, etc. Some specific examples of these polymerization initiators are as follows. Benzoyl peroxide, methyl ethyl ketone peroxide, acetyl peroxide, t-butyl hydroperoxide, di-t-butyl peroxide, cumene hydroperoxide, dicumyl peroxide, t-butyl perbenzoate, parachlorobenzoyl peroxide, cyclohexanone Peroxide, t-butyl acetate, etc. The amount of the polymerization initiator used is usually about 0.01 to 5% by weight based on the thermosetting resin of component A or the sum of this resin and the ethylenically unsaturated monomer. In addition, as the ethylenically unsaturated monomer, A)
Styrene, vinyltoluene, chlorostyrene, vinylstyrene, methyl methacrylate, acrylic acid, 2-hydroxyethyl acrylate, tetrahydrofuryl methacrylate, 2-ethylhexyl methacrylate, trimethylolpropane triacrylate, diallyl, which can be copolymerized with the component thermosetting resin. phthalates, and mixtures thereof. The amount of such monomer used is arbitrary, but to give an example, it is 20 to 250% by weight of the resin of component A),
Preferably it is about 40 to 140% by weight. In addition to polymerization initiators and ethylenically unsaturated monomers,
Furthermore, other compensating components can be added to the thermosetting resin depending on the purpose. Specific examples of such auxiliary components include solvents such as acetone, methyl ethyl ketone, dimethyl formamide, ethyl acetate and others, thermal polymerization inhibitors such as hydroquinone and others, ultraviolet absorbers such as 2,4-dihydroxybenzophenone,
2-hydroxy-4-methoxybenzophenone,
2-Hydroxy-4-n-octoxybenzophenone, "Tinuvin P" (manufactured by Ciba), other antioxidants, colorants, fillers or reinforcing agents such as glass fiber or its woven fabric, clay, carbon fiber, There are others. The thermosetting resin composition of the present invention can be molded into various molded products by, for example, films, sheets, boards, cast molding, injection molding, transfer molding, etc. using the above-mentioned curing method. The molded product thus obtained has high hardness and excellent heat resistance and electrical properties, so it can be used in a wide range of industrial fields. In addition, the thermosetting resin of component A obtained by carrying out the present invention does not rely on methylolation and methyleneation with formaldehyde for imparting thermosetting properties and thermosetting. Since polymerization of the introduced ethylenically unsaturated bonds can be prevented to the necessary extent, the various problems observed in the conventional melamine resins described above are solved. Hereinafter, the present invention will be explained in more detail with reference to Examples. Note that all parts in the examples are based on weight. Example of production of component A 1 In a 2-liter separable flask equipped with a stirrer, a distillation cooler, and a glass tube for blowing air,
390 parts of hexamethoxymethyl melamine (trade name "Cymel #303" manufactured by Mitsui Toatsu Co., Ltd.), 86 parts (1 mol) of methacrylic acid, 71 parts (1 mol) of acrylamide, 2.0 parts of para-toluenesulfonic acid, and 1.0 parts of hydroquinone methyl ether. The temperature was gradually raised while blowing air at a rate of 500c.c./min. Methanol began to distill from around 100℃, and the temperature rose further.
The temperature was maintained at 120-135°C. The amount of methanol is approximately 50-55
When the reaction temperature reached 70° C., the reaction temperature was lowered to around 70° C., and residual methanol was completely removed under reduced pressure.
747 parts of the product was a pale yellow transparent viscous substance 1. Examples 2 to 8 Table 1 shows the blending amounts of methacrylic acid and acrylamide.
Pale yellow transparent viscous substances 2 to 8 were obtained in the same manner as in Example 1, except that the proportions shown in . Examples 1-4, Comparative Examples 1-5 Transparent viscous materials 1-8 obtained in Production Examples 1-8
To 100 parts, 30 parts of styrene monomer and 1 part of benzoyl peroxide were mixed. This mixture is 300mm long.
The mixture was poured between 300 mm wide glass plates (3 mm gap) and cured at 80°C for 1 hour and at 120°C for 2 hours. Typical physical properties of these transparent cured products are shown in Table 1.

[Table] Example 9 of production of component A 383 parts (1 mol) of tetramexymethylbenzoguanamine (manufactured by Mitsui Toatsu Co., Ltd., trade name "Cymel #1123") and 86 parts of methacrylic acid were placed in the same apparatus as in Production Example 1.
(1 mole), 71 parts (1 mole) of acrylamide, 1 part of para-toluenesulfonic acid, and 1.0 part of hydroquinone methyl ether, and the mixture was heated and reacted while blowing air at a rate of 300 c.c./min. After the amount of methanol reached about 50-60 parts, the reaction system was cooled to 70°C. Furthermore, residual methanol was completely removed under reduced pressure to obtain 460 parts of a viscous pale yellow resin. Example 10 In a device similar to Production Example 1, 825 parts of methoxyetherified melamine polynuclear material (trade name "Cymel #325" manufactured by Mitsui Toatsu Co., Ltd.), 86 parts of methacrylic acid, 71 parts of acrylamide, and an acid catalyst (Mitsui 0.6 parts of Cymel #6000 (trade name, manufactured by Toatsu Co., Ltd.) and 0.6 parts of hydroquinone methyl ether were added and reacted in the same manner to obtain 834 parts of a viscous pale yellow resin. Examples 5 and 6 100 parts of the viscous pale yellow resin produced in Production Examples 9 and 10 above were blended with 30 parts of styrene monomer and 1 part of benzoyl peroxide to obtain a mixture. Table 2 shows the viscosity of these mixtures at 25°C. The physical properties of the cured product obtained by curing these mixtures in the same manner as in Example 1 are also shown in the same table.

【table】

Claims (1)

[Claims] 1. Component A: acrylic acid and/or α-lower alkyl-substituted acrylic acid, acrylamide and/or
Or a reaction product of a mixture with α-lower alkyl-substituted acrylamide in a molar ratio of 0.15/0.85 to 0.85/0.15 and an alkyl etherified melamine compound represented by the following general formula. [In the formula, R' each represents a hydrocarbon group having 1 to 4 carbon atoms, and R is a methyl group, a phenyl group,
N(CH ₂ OR') ₂ (R' is a hydrocarbon group having 1 to 4 carbon atoms, which is the same as or different from R' above), or an organic group represented by the following formula. (Y is -CH ₂ OR' or hydrogen, R' is a hydrocarbon group having 1 to 4 carbon atoms, which is the same as or different from R' above)] B Component: Polymerization initiator Heat composed of the above A) and B) components Curable resin composition.